Week 7- Ventilation and Gas Exchange

Question 1

What is a capacity?

Answer 1

The sum of two or more volumes

Question 2

What is a volume?

Answer 2

Discrete sections of a lung function graph that dont overlap

Question 3

What is minute ventilation and what is the formula for calculating it?

Answer 3

Gas entering and leaving the lungs

Tidal volume x breathing frequency

Question 4

What is alveolar ventilation and what is the formula for calculating it?

Answer 4

Gas entering and leaving the alveoli

(Tidal volume - dead space) x breathing frequency

Question 5

What is the usual minute ventilation?

Answer 5

6L/min

Question 6

What is the usual alveolar ventilation?

Answer 6

4.2 L/min

Question 7

What factors affect lung volumes and capacities?

Answer 7

Body size
Fitness
Age
Disease
Sex

Question 8

What is the conducting zone?

Answer 8

Equivalent to dead space, no gas exchange occours, 16 generation

Question 9

What is the respiratory zone?

Answer 9

Alveolar ventilation where gas exchange occours, around 7 generations

Question 10

What are non perfused parenchyma?

Answer 10

Alveolar dead space- alveoli without a blood supply, no gas exchange

Question 11

How can dead space volume be decreased?

Answer 11

Tracheostomy

Cricothyrocotomy

Question 12

How can dead space volume be increased?

Answer 12

Aneasthetic circuit

Snorkelling

Question 13

What membrane are the lungs surrounded by?

Answer 13

Visceral pleural membrane

Question 14

What is the inner surface of the chest wall covered by?

Answer 14

Parietal pleural membrane

Question 15

What is negative pressure breathing?

Answer 15

P alv is below P atm

Question 16

What is positive pressure breathing?

Answer 16

P alv is above P atm

Question 17

What type of breathing is normal breathing?

Answer 17

Negative pressure breathing

Question 18

What is the gap between pleural membranes called?

Answer 18

The pleural cavity

Question 19

Describe the pleural cavity

Answer 19

Has a fixed volume, contains protein rich pleural fluid

Question 20

What is transmural pressure

Answer 20

Pressure inside membrane - pressure outside the membrane

Question 21

What is Daltons law?

Answer 21

Pressure of a gas mixture is equal to the sum of the partial pressures of gases in that mixture

Question 22

What is Ficks law?

Answer 22

Molecules diffuse from a region of high conc to low conc at a rate proportional to the conc gradient, exchange surface area, diffusion capacity of the gas and inversely proportional to the thickness of the exchange surface

Question 23

What is Henrys law?

Answer 23

At a constant temp the amount of a given gas that dissolves in a given type and volume of liquid is directly proportional to the partial pressure of the gas in equilibrium with that liquid

Question 24

What is Boyles law?

Answer 24

At a constant pressure, the volume of a gas is inversely proportional to the pressure of the gas

Question 25

What is Charles’ law?

Answer 25

At a constant pressure the volume of a gas is proportional to the temperature of that gas

Question 26

What happens to gas as it moves down the airways?

Answer 26

Air is warmed, humidified, slowed and mixed

Question 27

What is oxygen delivery at rest?

Answer 27

16 mL/min

Question 28

What resting volume of oxygen do humans require?

Answer 28

250 mL/min

Question 29

Describe haemoglobin

Answer 29

Ferrous iron ion (fe2+) Ion at center of a tetrapyrole porphyrin ring Protein chain (globin) is covalently bonded at the proximal histamine residue

Question 30

What type of protein is Hb?

Answer 30

Allosteric

Question 31

What chemical helps Hb offload oxygen and how?

Answer 31

2,3 DPG, it makes Hb more tense

Question 32

What triggers more oxygen offloading?

Answer 32

Increased temp Acidosis Hypercapnia Increased 2,3- DPG

Question 33

What triggers more oxygen loading?

Answer 33

Decreased temperature Alkalosis Hypocapnia Less 2,3- DPG

Question 34

What is the medical term for difficulty in breathing?

Answer 34

Dyspnoea

Question 35

What is the medical term for cessation of breathing?

Answer 35

Apnoea

Question 36

What is the medical term for an abnormally slow breathing rate?

Answer 36

Bradypnoea

Question 37

What is the medical term for an abnormally fast breathing rate?

Answer 37

Tachypnoea

Question 38

Define anatomical dead space

Answer 38

The capacity of airways incapable of undertaking gas exchange

Question 39

What is hyperpnoea?

Answer 39

Increased depth of breathing to meet metabolic demand

Question 40

What is hypopnoea?

Answer 40

Decreased depth of breathing insufficient of meeting metabolic demand

Question 41

What is the medical name for positional difficulty in breathing?

Answer 41

Orthopnoea

Question 42

What 2 volumes added together give inspiratory capacity?

Answer 42

Tidal volume and inspiratory reserve volume

Question 43

What 3 volumes added together give vital capacity?

Answer 43

Inspiratory reserve volume Tidal volume Expiratory reserve volume

Question 44

What 2 volumes added together give functional residual capacity?

Answer 44

Expiratory reserve volume | Residual volume

Question 45

What 4 volumes added together give total lung capacity?

Answer 45

Inspiratory reserve volume Tidal volume Expiratory reserve volume Residual volume

Question 46

During inspiration is chest or lung recoil greater?

Answer 46

Chest recoil

Question 47

During expiration is chest or lung recoil greater?

Answer 47

Lung recoil

Question 48

What is pneumothorax?

Answer 48

Perforated chest wall

Question 49

What does a negative transrespiratory pressure lead to?

Answer 49

Inspiration

Question 50

What does a positive transmural pressure lead to?

Answer 50

Expiration

Question 51

What does FEV1 resemble?

Answer 51

The proportion of vital capacity that is exhaled in the first second

Question 52

Rank the gases from least to most abundant in air out of argon, oxygen, carbon dioxide, nitrogen

Answer 52

Carbon dioxide Argon Oxygen Nitrogen

Question 53

Describe oxygen binging to haemoglobin

Answer 53

The first O2 molecule has a low affinity to bind but as each O2 molecule binds affinity increases as the haemoglobin becomes more relaxed

Question 54

What does a high heart rate with saturated arterial blood indicate?

Answer 54

An oxygen delivery problem

Question 55

What is the Bohr shift?

Answer 55

A rightwards shift of the oxygen dissociation curve

Question 56

Why may the oxygen dissociation curve shift downwards?

Answer 56

Due to impaired oxygen carrying capacity eg anaemia

Question 57

What would a downwards and inwards shift of the oxygen dissociation curve suggest?

Answer 57

Decreased capacity and increased affinity eg increased HbCO

Question 58

How do the affinities of foetal Hb and myoglobin to oxygen differ from normal haemoglobin

Answer 58

Both have a higher affinity

Question 59

When RBCs reach the lungs how saturated are they?

Answer 59

75%

Question 60

What do carbon dioxide and water combine to give in blood vessels?

Answer 60

Carbonic acid

Question 61

In RBCs what enzyme helps form carbonic acid from carbon dioxide and water?

Answer 61

Carbonic anhydrase

Question 62

When carbonic acid dissociates, what does the H+ help form?

Answer 62

Carboaminohaemoglobin

Question 63

What is pulmonary transit time?

Answer 63

The time it takes for a molecule of Hb to cross the gas exchange surface

Question 64

What effect does type 1 diabetes have on the oxygen dissociation curve and why?

Answer 64

Moves it to the right due to ketoacidosis (increased acidity)

Question 65

What effect dies increased tidal volume have on the conc of oxygen dissolved in the blood?

Answer 65

Increases the conc of oxygen dissolved in the blood